SE454945B - AGGLOMERATED PARTICLES OF A DENTAL POLISHING INTENDED TO BE INFORLIVED IN TOOTH CREAM - Google Patents

Abstract

Functional agglomerated speckles, for incorporation in dentifrices, include agglomerates of a water insoluble powdered functional material and water insoluble, ethanol soluble ethyl cellulose, and may sometimes preferably also include a water soluble binder, such as polyvinyl pyrrolidone. Such speckles satisfactorily maintain their integrity and identity during processing of the dentifrice after addition of the speckles to a main dentifrice body but on storage, after packaging of the dentifrice in dispensing tubes, soften sufficiently so as to become essentially impalpable to one utilizing the dentifrice in brushing his teeth. Despite such softening the speckles continue to maintain their identity as speckles in the dentifrice. The speckles are especially useful in translucent or transparent gel dentifrices which contain components, such as flavouring and surface active agents, which may controllably soften the speckles on storage.

Description

However, it does not provide a particle that maintains its integrity during prolonged product preparation.

A toothpaste containing encapsulated sweetener has been described in the art, mentioning ethylcellulose among various other materials as useful in encapsulating sweeteners and making spheres. Water-soluble and water-insoluble binders for dental particles have been described simultaneously in this technique, but ethylcellulose has not been mentioned. Toothpaste compositions with visible agglomerated particles of dental abrasive dispersed therein are known, and the benefits of both water-soluble and water-insoluble agglomerating agents or binders have been described, but ethylcellulose has not been stated to be useful in these descriptions. Microencapsulation of sodium fluoride using lower alkylcellulose, such as ethylcellulose, and dispersion of the capsules in a toothpaste have been proposed, but this proposal was not related to agglomeration of materials for the production of dental particles.

The functional agglomerated particles according to the invention, intended to be incorporated in toothpaste, are defined in claim 1 and embodiments of the invention are stated in the dependent claims.

Thus, according to the present invention, ethylcellulose, which is insoluble in water but soluble in ethanol, is used as an agglomerating agent for a functional water-insoluble powdery material in the production of toothpaste particles with improved properties. Previous particles, made with water-soluble binders such as methylcellulose, could dissolve during the processing process after being mixed with other toothpaste components, such as those in the pre-prepared gel or paste medium, if the particulate toothpaste was retained for too long in the preparation container, which can happen when mechanical malfunctions occur. The loss of the integrity of the particles can occur due to the toothpaste containing water that can solubilize water-soluble binders in the particles. which leads to the different components of the particles separating. The dissolution of the binder can in such a case be reduced to a minimum through a fast treatment procedure, but when a break in the filling line causes extended process times, this can result in product loss. Toothpaste particles prepared with common water-insoluble binders, as described in the art (which, however, do not mention ethylcellulose), tend to become noticeable when dispersed in a toothpaste gel or paste, and although this may often be desirable, it does not apply to certain toothpastes, such as those intended for people with sensitive gums.

The ethylcellulose used as a binder in the functional particles of the present invention satisfactorily maintains the integrity of the particles in an aqueous toothpaste medium for a time long enough to allow product preparation after incorporation of the particles into the toothpaste. Probably due to the presence of components in the toothpaste, which tend to soften the particles during storage, such as flavors and in some cases surfactants, the particles in the toothpaste are softened sufficiently during storage so that they, even if they maintains its integrity and independence and is distinctly separated from each other until the product is used, becomes imperceptible and easily disintegrates during toothbrushing.

In certain preferred compositions, such as those which may contain minor quantities of flavors (and dental detergents and other solvents or lipophilic agents) or in such toothpastes which include less soluble materials (such as ethylcellulose) the presence of an auxiliary binder that is water soluble, eg PVP, achieve the desired imperceptibility. However, the integrity of the particles will be maintained due to the presence of ethylcellulose.

Once prepared, preferably by a process comprising "wetting" a water-insoluble functional material in powder form (or a mixture of the functional powder and water-soluble binder) ethylcellulose in a flight conversion to batch with a solution of water-insoluble solvent, compaction, kelform and drying, the particles can be transferred in a controllable manner to a stream of toothpaste and adhere to it to be evenly distributed therein, and preferably a special apparatus is used here.

The functional agglomerated particles consist of two main components: a water-insoluble powdery functional material and a water-insoluble ethanol-soluble ethylcellulose. The first component can be characterized as the functional concrete material and the second as the binder. Various functional materials, all of which are preferably insoluble in water or at least slowly soluble, may be used, including dyes such as pigments, germicides, ion exchange substances, polymeric materials (which may also contain other active components, in some cases water-soluble materials), and flavoring agents, but it is highly preferred that the functional base material in the particles be a polish or include a large portion thereof. Of the polishes which are usually used in the form of a dry powder in the preparation of the agglomerated particles, dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, silica, magnesium carbonate, calcium carbonate, calcium carbonate, calcium sulfonate, calcium carbonate, Both anhydrous or calcined forms of these materials, such as calcined alumina, and hydrated forms, such as dicalcium phosphate dihydrate, can be used, but the anhydrous or calcined materials are often preferred. Since the agglomerates are usually preferably opaque, there is no need to adapt these refractive indices to the toothpaste vehicle (also including other components), but "transparent" polishes with such an adapted refractive index, eg 1.44 - 1.47, can be used. to obtain transparent or semi-transparent particles and also in the production of a clear toothpaste gel containing polish. The "transparent" polishes include colloidal silicic acids and those sold under the Syloid brand, such as Syloids 63, 65, 72 and 74, under the Santocel brand, such as Santocel 100, and the Zeo products 49, 113 and 119, and Zeodent. In addition, synthetic alkali metal-aluminum silicate complexes may be particularly suitable because their refractive indices are close to those of dental vehicles including water, glycerol, sorbitol and gelling agents, which are those commonly used in the manufacture of toothpastes.

The water-insoluble powdered functional material used in the preparation of the particles in question should generally initially have a particle size in the range 0.5 to 20 microns, preferably in the range of 1 to 10 microns and in particular 2 to 8 microns. . In some cases, however, larger particles can be used, such as when! The agglomeration process tends to reduce the size of a portion of the powder, which may be the case with mixing before the agglomeration itself begins.

The binder in the particles in question is ethylcellulose. This effective binder is insoluble in water but soluble in ethanol, and it slowly dissolves in an aqueous glycerol sorbitol medium which also contains "solvents" therefor, such as flavors and surfactants, which are generally present in the toothpastes of the present invention. . The ethylcellulose should usually have an ethoxy content in the range of about 45-50%, preferably 48-50% or 48-49.5%. In a preferred ethylcellulose, such as that sold by The Dow Chemical Company under the trademark Ethocel Standard 10 Premium Ethylcellulose, the ethoxy content is in the range of 48.0-49.5%; the viscosity is 9 - 11 cP; the moisture content is a maximum of 2%; the chloride content, such as NaCl, is a maximum of 0.15%; and the ash content is a maximum of 0.15%.

Ethylcellulose resins, suitable for use as binders in the particles in question, are commercially available in the form of white to light brown granulated powders with a degree of etherification such that there are 2.25 - 2.58 ethoxy groups per anhydrous glucose unit, corresponding to 45.0 49.5% by weight of ethoxy content. Of two such grades of ethylcellulose, in carrying out the process according to the invention, those materials having an ethoxy content in the range 48.0 - 49.5% by weight are preferred over those having an ethoxy content in the range 45.0 - 46.5%. weight-%. These products can, of course, have different viscosity ranges, usually between 3 and 110 cP, with the least preferred materials being those which tend to be more viscous.

The preferred or "standard" grade of ethylcellulose tends to be soluble in aromatic hydrocarbons, hydroaromatic hydrocarbons, chlorinated aliphatic hydrocarbons, and turpentine and the like. It is also soluble in aliphatic monohydroxy alcohols, such as ethanol; cyclic monohydroxy alcohols such as benzyl alcohol, phenylethyl alcohol and tall oil; ether alcohols such as glycol ethers; ethers such as diethylcellosolv; esters, in particular acetates such as isopropyl acetate and sec-amyl acetate and esters of hydroxy acids such as methyl salicylate; and in ketones such as cyclohexanone and acetophenone. In general, the less preferred or "medium" grade of ethoxyethylcellulose is less soluble than the standard grade and may therefore be suitable for use when higher levels of solubilizing material are present in the toothpaste composition.

The water-soluble binders useful in the combination of binders which are sometimes preferred in the preparation of the particles of the present invention include, inter alia, gum arabic: gelatin; starch, both natural and modified; alkali metal carboxymethylcellulose, especially sodium carboxymethylcellulose; polyethylene glycols; sugars such as glucose and sucrose; methylcellulose; carboxyethylhydroxyethylcelluloses; alginates, in particular sodium alginate; polyvinyl alcohol; carrageenan, preferably Irish moss; xanthan gum; gummidragant; and PVP. It has been found that PVP is stable in the presence of ethylcellulose, that it does not bleed excessively from the particles in which it is included as a binder in combination with ethylcellulose, and that it can be used to adapt the binding properties of the combined binder. so that given binder can be easily modified to be used in the same desired total content in different toothpaste compositions, in which the ratio of ethylcellulose to PVP can thus be regulated. An important property of the combination of binders in the particles in question is further that this gives sufficiently hard and strong particles, which are not excessively dissolved during product preparation, but nevertheless during storage are sufficiently softened in the toothpaste in which they are included, so that it does not become noticeable at the time of use of the toothpaste. They are not softened to such an extent that they form streaks in the tube or when they emerge from it, but by adjusting the quantity of ethylcellulose in relation to PVP, increasing the quantity of PVP, a controlled streaking can be obtained in some cases if desired.

PVP generally has a molecular weight in the range of 30,000 - 50,000, and the PVP preferably used in the present invention has a molecular weight of about 40,000.

Such a product, sold by GAF Corporation under the trademark Plasdone, such as Plasdone K 29-32 and K 26-28, has the average molecular weights given in K-values, whereby x-ao ä; - iike with ee 40 ooo . PvP is available in the form of a light colored powder containing less than 5% moisture, 12.6; in 0.4 a, nitrogen, less than 2 ppm arsenic and less than 20 ppm heavy metals. It is soluble in cold water and in various organic alcohols, acids, ether alcohols, ketone alcohols, chlorinated hydrocarbons, esters and ketones, but insoluble in hydrocarbons and certain ethers, chlorinated hydrocarbons, ketones and esters. It is compatible with various natural and synthetic resins, inorganic salts and with many synthetic organic detergents, including those commonly used as dental detergents, such as higher sodium fatty alcohol sulfates and lower polyalkoxylated alcohol sulfates. Although the best particles could be expected to be made from the least soluble binder, ethylcellulose, as described herein, has been found to provide particles with ideal properties, which particles retain their individuality and integrity during preparation and storage. but also is virtually imperceptible 10 15 20 25 30 35 454 945 when brushing with the toothpaste. If desired, the nature of the particles can be changed, for example by modifying the ethoxy content of the ethylcellulose and / or by mixing it with other substantially water-insoluble binders of known type. Similarly, when the content of lipophilic material in the toothpaste (smaller amount of particles) is small, so that the particles are less likely to become imperceptible during storage, a water-soluble binder, eg PVP, can be used together with the ethylcellulose to increase the softening of the particles. The properties of the particles can also be regulated by using additional water-soluble (water-soluble) binder or a larger amount of such (such) binder, or by changing its molecular weight (such as by reducing the molecular weight of PVP). The properties of the particles can also be regulated by changing the ratio between functional material and binder, which will be described later. Thus, agglomerates can be prepared which are stable during product preparation after mixing, such as deaeration and filling, but which dissolve rapidly after the toothpaste is squeezed out of its container or, if desired, this solution can be delayed so that the agglomerate will feel harder and slightly more resistant when the consumer brushes his teeth. In general, it is highly desirable that the particles be substantially imperceptible in use, while still retaining their identity in the toothpaste.

The binder should usually have the same particle size as the functional powdered material in the particles, especially if the agglomerate, at least in part, is produced by compressing powdered materials.

Since the particles are generally prepared using an alcoholic solution of the ethylcellulose, the particle size may have a relatively small significance. However, when water-soluble binder is present, its particle size 454 945 10 15 20 25 30 35 10 should be the same as that of the functional material. Although the particles are sometimes white or colorless and possibly even translucent or transparent, or have a similar appearance, they may also be colored because they contain an appropriate quantity of dye or pigment, or a mixture of dyes and / or pigment. Any non-toxic dye or pigment of suitable color, usually a strong color, such as something of a suitable shade and having a Munsell dye strength greater than 4 and a Munsell value in the range of 4 to 7, may be used, and in some cases may be soft. colors or pastel colors be satisfactory or desirable. It is generally best to use a dye or pigment that is approved for medical and cosmetic use (D&C) or for use in food, medicine and cosmetics (FD & C). Examples of suitable dyes are D&C Red Nos. 2, 3, 6, 7, 8, 9, 10, 11, 12, 13, 19, 30, 31, 36 and 37; D&C Blue No. 1; FD&C Blue Nos. 1 and 2; FD&C Red Nos. 1, 2 and 3; FD&C Yellow No. 5; cosmetic green oxide: and cosmetic red oxide. Pigments of said dyes, termed substrate pigments, can also be used in coloring the particles, but in general the dyes are preferred. The pigments mentioned often consist of dyes on a finely divided powdered insoluble carrier, and the pigments are dispersed rather than dissolved in the medium to be dyed. The particle size of the pigments used may be within the range previously indicated for the polishes, or may be the same as that of the binder. The size can be finer, for example in the range 0.01 - 1 micron. The particle size of the dyes may be the same, but since these are usually used in the dissolved state, in water or solvent, preferably being oil-soluble and dissolved in the suitable solvent, the particle size is not important as long as the powder or particles are small enough. to render the dye readily soluble in the selected solvent. The particles of the present invention can be prepared in any suitable manner, either by a wet or a dry process. When ethylcellulose is the only binder and a wet granulation process is applied, the ethylcellulose in the form of a dry powder is preferably mixed with the polish and the dye or pigment, if any, and ethanol. Water and / or lipophilic solvent may be present together with the ethanol, and a dye or pigment for coloring the particles may also be present. Alternatively, and often preferably, a suitable dye or pigment as well as the polishing agent may be included in the ethanol solution of ethylcellulose. The ratio of the components should be such as to obtain particles of the desired composition, and the content of one or more solvents should generally be 5 to 50% of the mixture, preferably 5 to 25% thereof. The dispersion can be prepared by means of a Hobart mixer, Dravopanna or other suitable mixing device or granulator for wet (wet) powder, and the order in which the various components of the dispersion are added can be adapted to best suit it. use the mixer or mixer. A preferred way of preparing the particles is to force the "moistened" mixture of polish and ethylcellulose (with dye or pigment if used) through a sieve with smooth openings, which should generally have a size of about 150 - 2000 microns (about sieve area no. 10 - 100 in the US sieve series), after which the extruded agglomerate is dried, usually either in the air or in an oven. Instead of sieves, other devices, such as an injection molding machine, can be used to ball the blender or otherwise ball sinter the mixture, after which the resulting particles are dried. The particles are then divided into desired size ranges, generally in the range Nos. 10 - 80, preferably Nos. 40 - 80 and in particular Nos. 30 - 60 (according to the American screen series). If the wet mass is formed in a Dravo boiler, the sieving under pressure or extrusion can of course be omitted. If the particle size is larger than 2000 microns (sieve No. 10), it is generally less attractive for a consumer to insert the particles into the oral cavity, and if it is less than about 177 microns in diameter (sieve No. 80), the particles are not as easily visible and have consequently not the same attractive appearance.

Instead of applying the wet granulation process, a dry method or compression method can be used, in which the components of the particles are pressed to a large tablet size, and the tablet can then be crushed, whereupon the particles of the desired size are separated from the others. In this tablet preparation, it may be desirable to use a water-insoluble lubricant, such as talc, magnesium stearate, calcium stearate or stearic acid, which also facilitates agglomeration. Such materials and other water-insoluble aids may also be present when a wet granulation method is applied. The particles produced are preferably dry and contain no moisture, but moisture contents of up to 10%, eg 1 - 5%, can occur without having any more serious adverse effect on the properties of the particles.

The ratio in the particles between water-insoluble powdery functional material, such as dental polish, ethylcellulose such that the binder and the powder and binder, such as ethylcellulose or plus water-soluble binder, should be the agent constitute a minor part of the particulate functional material constitute the largest part hence (although one must also take into account the presence of other materials, such as dyes and aids). In general, the dental polish or functional material constitutes from 75 to 80% to 98% of the particles, preferably 85 - 97% thereof, the binder or combination of binders constitutes 2 - 20% of the particles, preferably 10 15 20 25 30 3 - 15% thereof, and the dye constitutes 0 - 5% of the particles, such as about 0.05 - 1% thereof, all on a dry basis, free from water and ethanol or other solvent. When a combination of binder is present, the ratio of ethylcellulose to water-soluble binder (PVP) is between 1:10 and 10: 1, preferably 1: 5 to 5: 1, more preferably between 1: 2 and 2: 1, and most preferably between 1: 2 and 1: 1, eg 2: 3.

The toothpaste in which the particles are distributed may be any suitable such product, since in accordance with the present invention it essentially constitutes a medium for the particles, which retains them unaffected, individual and separated from each other, while having its normal function as a toothpaste. . Opaque toothpastes are a useful medium for the particles in question, but it is much more expedient if the toothpaste is transparent or semi-transparent and is generally of the type characterized as a gel. Toothpaste normally contains water, humectants, gelling agents, dental detergent and a dental polish, and generally also a flavoring and / or coloring agent. Among the various functional additives are fluorides, stabilizers, anticancer agents and antibacterial compounds.

The water used should preferably be deionized water, although tap water, both soft and hard, can also be used. The gelling agent is usually a water-soluble natural or synthetic rubber or rubber-like material, among which may be mentioned carrageenan, gum tragacanth, xanthan gum, alginates, alkali metal carboxymethylcellulose (preferably sodium carboxymethylcellulose), hydroxymethylcarboxyethylcellulolide, polyvinylpyrrolecolylide 45 25 9 454 945 14 are sold under the trademarks Carbopol 934 and 940. Although various polyols can be used as humectants, they are preferred with 3 to 6 carbon atoms and 3 to 6 hydroxyl groups per molecule, and those which are preferably selected are glycerol and sorbitol. Glycerol is normally in the liquid state and has a purity of about 99% or more, and sorbitol is normally a solid which is commonly used in the form of a 70% aqueous solution (70% sorbitol, 30% water).

The three components mentioned can be considered as the main constituents of the toothpaste vehicle, in which flavors and detergents can also be mixed. The detergent may include soap, but in general it is a non-soap-containing synthetic organic surfactant with a cleaning ability. Preferably the detergent should be of the anionic type, although nonionic detergents are also useful, ampholytic detergents may be used and cationic detergents may be accepted under certain circumstances.

The preferred anionic detergents are particularly suitable because they combine excellent cleansing action with excellent foaming properties. Usually these compounds consist of balanced hydrophilic and lipophilic moieties, the lipophilic moiety generally being a higher fatty alkyl or acyl group having 10 to 18 carbon atoms, preferably 12 to 16 carbon atoms, and the hydrophilic moiety being an alkali metal, eg sodium, potassium or ammonium or lower alkanolammonium. Suitable anionic detergents are: water-soluble salts (generally alkali metal and preferably sodium or potassium) of higher fatty acid monoglyceride sulphates, such as the sodium salt of the monoglyceride monosulphate of hydrogenated coconut oil fatty acids; higher alkyl sulfates such as sodium lauryl sulfate; alkylarylsulfonates such as linear sodium dodecylbenzenesulfonate; higher alkyl sulfoacetates; higher fatty acid ester-1,2-dihydroxypropanesulfonates; the sodium salts of sulfated polyethoxylated alcohols; and the substantially saturated higher aliphatic acylamides of lower aliphatic amino-carboxylic acid compounds such as the N-lauroyl sarcosine and the sodium, potassium and ethanolamine salts of the N-lauroyl, N-myristoyl and N-palmitoyl sarcososin preferably are substantially free of soap or similar higher fatty acid materials. Among the useful nonionic detergents may be mentioned ethoxylated sorbitan monostearate with about 20 moles of ethylene oxide per mole; condensate of ethylene oxide with propylene oxide and propylene glycol (Pluranics); polyethoxylated higher fatty alcohols such as Neodols (23 - 6.5 and 45 ~ 11 for example); and condensation products of alpha-olefin oxides having 10 to 20 carbon atoms, polyhydroxy alcohols containing 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, and either ethylene oxide or heterogeneous mixtures of ethylene oxide and propylene oxide. Quaternized imidazoyl derivatives. such as Miranol CZM, and other Miranols are useful amphoteric detergents, and the quaternary ammonium halides, such as dimethyldicetylammonium bromide, are examples of cationic detergents.

The various polishes dispersed in the toothpaste vehicle (or vehicle plus detergent and possibly other additives) are those previously described as being suitable for conversion to particulate form. Also useful in this group of materials are synthetic atomized silicas, such as those sold under the trademarks Cab-O-sil M-5, Syloid 244, Syloid 266, Aerosil D-200, Zeosyl 200 and Zeothix 265, which are usually very low percentage is included in the polish, generally not more than 1-9% by weight of the total toothpaste, and which can be used to thicken or gel the vehicle and to improve the clarity of the toothpaste.

The toothpastes in which the particles are to be incorporated must generally contain suitable flavoring and / or sweetening agents.

Examples of flavors are aromatic oils, such as oils of green mint, peppermint, evergreens, sassafras, cloves, sage, eucalyptus, cinnamon, lemon and orange, and sweeteners include sucrose, lactose, maltose and saccharin. . Fluoride toothpastes preferably also contain sodium fluoride, tin fluoride, potassium fluoride, potassium tin fluoride, sodium hexafluoro stannate, stannous fluoride and / or sodium fluorophosphate.

The flavors include various well-known essential oils, mainly terpenes; estrar; alcohols, aldehydes, ketones and other aromatic substances, many of which emit aromatic odors. Since taste is both a physiological and psychological reaction conditioned by the presence of a substance in the mouth and is associated with both taste, smell and touch, whereby smell is often of primary importance, it is not surprising that aromatic materials are important taste components. . In the present case, advantage has been taken of this relationship and of the chemical nature of these materials, as previously indicated in the discussion on the solubility of ethylcellulose, since this allows the ethylcellulose binder in the particles in question to be slowly solubilized by the solubilizing substances in the flavoring agent. the material, whereby the particles are softened but not decomposed. For example, the terpenes, which are hydrocarbons and which constitute an important class of perfume or flavoring materials, are good solvents for the ethylcellulose of the present invention, as are many other flavoring materials, such as those mentioned above (e.g. aromatic oils). ), and other known materials in the fields of perfume and taste. By using flavoring essences in the toothpaste composition to soften the ethylcellulose in the particles and thereby rendering them imperceptible, which is the object of the present invention, it becomes unnecessary to add any other component to the toothpaste or particles to achieve this purpose. In addition, due to the relatively low content of flavoring material usually present in a toothpaste, the lipophilic portion of the flavoring being often the smaller portion, a desired slow softening of the particles can be achieved, usually due to of a relatively low substance transfer rate of the "dissolving" material, which transfer rate is mainly due to the gelatinous consistency of the toothpaste. Although some flavoring materials at the interface of the particle begin to soften the ethylcellulose therein during the mixing of the toothpaste, the solution of ethylcellulose in the flavoring will soon be saturated, thus preventing further rapid dissolution of the ethylcellulose.During the normal shelf life of a toothpaste before it is sold and used, a time which is often at least about 2 weeks and sometimes longer (then In the case of certain toothpastes, it is desirable that these are subjected to aging to improve the taste and h immaturity), the particles become imperceptible, but remain distinct.

The above discussion has concerned the ethylcellulose binder, but in some cases it is appropriate that a water-soluble binder, such as PVP, be present, and the description is also intended to include such particles and particulate toothpastes. In such products, the ethylcellulose holds the particle together until it is "solubilized" by the lipophils in the toothpaste, and PVP means that less ethylcellulose can be used and facilitates the desired softening of particles in toothpastes containing lower levels of solubilizing flavor and other lipophils. . Although the flavoring materials, and in particular the lipophils which have a truly dissolving effect on the ethylcellulose, are considered to be the most important slowly solubilizing components of the toothpastes in question, the surfactant component which includes a lipophilic moiety Also have a significant solubilizing effect, and due to its wetting effect it can facilitate the transfer of substance into a toothpaste tube and thereby increase the solubilization rate of the ethylcellulose. It is also possible that combinations of other constituents of the toothpaste, including some of the sweeteners and the vehicle components, further contribute to the solubilization of the ethylcellulose to the desired extent, without promoting premature softening of the particles.

Dyes, such as those previously mentioned with respect to the particles, can also be used, normally in smaller concentrations, to obtain a base which contrasts with the particles. Various other additives can be included in the toothpaste, including preservatives, silicones, chlorophyll compounds and ammonified materials. When producing a toothpaste gel that is to be transparent or semi-transparent, one should usually choose as the polishing agent one whose refractive index is close to the same for the other toothpaste medium. In such clear gel compositions, of course, the present amount of insoluble material which may obscure the gel should generally be reduced to a minimum.

When adjusting the pH value of the toothpaste, which is preferably in the range 3 - 10, and even more preferably between 3.5 and S when stannous ions are present and between 4.5 and 7 in the absence of such ions, organic acids can can be used, such as citric acid, malonic acid and fumaric acid.

In the toothpaste of the present invention, a dental polish is evenly distributed in the vehicle of water, humectant and gelling agent, with a dental detergent and the desired level of flavor already mixed.

Thereafter, the particles, which also preferably contain a polishing agent (and often of a different type than that in the main mass of the toothpaste), are evenly distributed in the toothpaste in a quantity which usually amounts to 0.1 - 10% of the toothpaste. The cream, preferably 0.5 - 5% thereof, more preferably 1 - 3% thereof and most preferably 1.5 - 2.5% thereof. The main mass of the toothpaste generally consists of: about 5 - 30% water, preferably 10 - 25% and in particular 10 - 20%; about 20-70% humectant, preferably a polyol humectant, more preferably 45-65% thereof and most preferably 50-60% thereof; and about 0.1 - 5% gelling agent, preferably 0.1 - 1% and in particular 0.2 - 0.5% thereof.

The humectant preferably consists of a mixture of glycerol and sorbitol, the glycerol content being 5 - 40% of the toothpaste base, preferably 20 - 30%, and the sorbitol content is S - 50%, preferably 25 - 35%. The preferred gelling agent is sodium carboxymethylcellulose and a preferred content thereof is about 0.3-0.4%.

The content of dental detergent is generally between 0.5 and 5%, preferably 0.5 - 3%, and a preferred such detergent is sodium lauryl sulfate. The polish in the toothpaste base, excluding that in the particles, is generally 10 - 40%, preferably 15 - 30% and most preferably 20 - 25%, including silica of the type Syloid 244, which is also used as a thickener. Various other materials, including flavorings (usually 0.5 - 2%), dyes, preservatives, sweeteners, dentifrices (fluorides), should generally not total more than 10% of the toothpaste and are preferably between 2 and 7%. % thereof. When using the contents of the various constituents within the given areas, in terms of the particles and the medium in which they are distributed, an attractive product is obtained, which is stable during storage and in which the particles are evenly and appealingly distributed.

Making the spotted toothpaste, after the particles have first been produced, is comparatively simple, but an important thing is that the least possible mechanical agitation should occur to prevent or delay disintegration, softening. and solubilizing the particles in the toothpaste. The intention is that the lipophilic materials and solvents present, such as those present in the aromatic oils, should slowly solubilize the ethylcellulose, but not to an excessive degree and in the absence of vigorous stirring during product preparation. If the toothpaste has an elevated temperature during mixing, possibly due to manufacturing tolerances in the process, it is even more important to reduce the agitation to a minimum. When ethylcellulose binder or the combination of binders is used in the production of the particles, the restrictions on manufacture are less stringent, but care must be taken. A suitable device for distributing the particles in the toothpaste is conventional Banbury or dough mixers, which operate at low speeds, but other gently working mixers can also be used provided that the mixing takes place under control to prevent decomposition, dissolution or decomposition. of the particles. When such mixers are used, the mixer wing should generally have a speed of 1 - 5 rpm, and the mixing should last for 1 - 5 minutes. After mixing, the toothpaste is deaerated and filled into containers, such as translucent elastic or compressible tubes. If mixing takes place in a vacuum, deaeration can be excluded. Although the apparatus and method of preparation as above are conventional in the manufacture of dotted toothpastes, it is advantageous to apply methods recently developed to facilitate the incorporation of the particles into the toothpaste gel without excessive agitation.

Such processes and apparatus, as well as other objects of the present invention, will become apparent from the following description and the remainder of this detailed description, which make it easy to understand the meaning of the invention, with reference also to the accompanying drawings, in which: Is a perspective view of a tube for a toothpaste gel according to the present invention, including a removed tube cap and a toothbrush; Fig. 1 schematically shows a device according to the invention for producing spotty toothpaste Fig. 2 starting from a dental composition and pre-produced particles; is an enlarged perspective view of a portion of the "particle addition device" of the invention, illustrating the addition of particles to a stream or band of gel; Fig. 3 Fig. 4 is a schematic view of another device according to the invention for producing a spotted toothpaste; and is an enlarged perspective view of a portion of the "particle adding device" of Fig. 4, illustrating the addition of particles to a stream or band of gel.

Fig. 1 Fig. 1 shows a container 11 with transparent walls, made of a transparent polymeric material (PVC) and consisting of a body 13, a plate 15, a threaded neck 17 and a tube cap 19, the tube cap being removed from the tube. Although the toothpaste is preferably packaged in a deformable tube of clear or translucent synthetic organic polymeric material, such as polyvinyl chloride, polyethylene, polyvinylidene chloride or similar materials, through which the attractive appearance of the spotted toothpaste is visible, compressible opaque tubes can also be used. , such as those of aluminum or any other metal.

As can be seen, some toothpaste 21 has been portioned out of the tube 11 via the neck 17 of the toothbrush 12. Particles 23 10 15 20 25 30 35 454 945 ~ 22 according to the invention are clearly visible in the toothpaste and in the continuous strand of toothpaste 25. It should be noted - that the dots or particles are not perceptible from the outset, even if they can be clearly seen. During toothbrushing, they are crushed into smaller units of substantially the same size as the polish component. The polish in the particles naturally interacts with the same in the dental gel to help clean and polish the teeth.

Fig. 2 shows the gel mixer 111, which is often preferably a Hobart or Dopp mixer, in which the various components of the dental composition, including the vehicle, gelling agent, polish, flavor, color, detergent, preservative and any other additives, are mixed together. , sometimes under vacuum, to form a composition in which particles, preferably functional particles such as those based on dental polish, are mixed to give a dotted toothpaste. A motor with speed control and / or variable speed 113 drives a positive forwardly projecting pump 115, with controllable speed, which pump transfers the gel to an outlet 117, preferably a slightly restricted flat opening, through which it is sprayed or discharged in the form of a flat tape or any other suitable stream 119, to which particles 121 in discrete or comminuted form are applied. The pump 115 can be set to control the feed rate of the gel, and also by controlling the feed rate of the particles, the desired proportion of particles can be continuously added to the liquid gel. Preferably, the pump 115 is such that it exposes the gel to only slight or no shear stress so that it maintains its consistency (viscosity), and screw pumps with elastic walls are preferred, such as those of the Moyno type. The gel dispenser or syringe 117 is preferably enclosed in a surrounding vessel or container 123 and is usually located so that the gel strips produced in the container, with particles applied to the surface thereof, falls vertically onto the bottom of the container near the center thereof, from which they are removed via a central outlet 125.

The particles to be added to the dental gel in a predetermined quantity are contained in a hopper 127, provided with a control device 129 with adjustable speed, preferably of spiral type, including a speed regulator 131, which feed device with controlled speed discharges the particles via a outlet 133 in a funnel-shaped device 135, which desirably forms the outgoing stream of particles so as to form a descending stream or curtain corresponding to the band of gel flowing out of the outlet 117, and is preferably such that the particles fall substantially vertically for to be deposited on and adhered to the inner part of the gel band, without missing contact with the gel anywhere.

Preferably the curtain of particles covers the main part, for example 40-95% and preferably 60-90% of the width of the gel band, and the curtain should not be so wide that any larger part of the particles misses the band. However, it is desirable that the curtain has a width which is only insignificantly smaller than the width of the belt, if possible, eg 80-90% thereof. Lines 137, 139 and 141 are connected to vacuum sources 143 and 145, respectively, but although the use of vacuum is desirable to prevent air bubbles in the toothpaste, gentle infiltration can prevent the infiltration of such bubbles without using vacuum.

After the particulate toothpaste has fallen through the outlet 125, a pump 147, which is preferably a Moyno-type screw pump driven by a variable speed motor 149, gently transfers the product to a static mixer 151, preferably by Kenics. type, where it is gently mixed without decomposition or solubilization of the particles therein into a homogeneous mixture. It is then led through a line 153 to a container 155, which may be a feed tank for a tube filling machine, not shown.

Fig. 3 shows a feeding device 157 consisting of a feed tube 159 and a nozzle 117, which has a flat, rectangular shaped opening 161. The feeding device for the gel and the opening in the exhausting part of the nozzle can be adjusted. The feed direction can thus be set as desired, and the feed angle can be varied, but the feed direction should have a horizontal component and is generally between o een 4s °, eg 10 - 3o °, 1 in relation to the horizontal number line. The rectangular opening can also be changed with respect to size, so that it is reduced, but care must be taken that the gel remains coherent so that the thickness of the strip does not fall below its strength.

Generally, it should have a thickness of from 1 mm to 1 cm, eg 2 - 6 mm. The gel band is directed so that the stream or curtain of particles can fall thereon in a proper manner, and preferably the particles are allowed to fall substantially vertically while the gel is moved in a direction with a horizontal component, so that the gel passes under the falling particles which come into contact with and adheres to the same. The gel band 163 is shown here falling downwards to the right, while the particles 165 fall down on the same from an outlet pipe 167 of the aligning device 135 (Fig. 2).

Fig. 4 shows a vessel 211 for the gel preparation, which may be the same as in Fig. 2 and function in the same way.

The valves 213 and 215 on the line 217 together with the positive feed pump 219 at adjustable speed enable a recirculation of the gel to the mixer, if desired. The lines 220 and 221 and the valves 222 and 223 make it possible to empty the dental gel (or paste) during cleaning or to produce a toothpaste which does not contain particles. When the valves 215, 222 and 223 are closed and the valve 213 is open, the gel pump 219 operates and the mixing device 211 contains dental gel, the line 225 and the valve 227, when open, allow the gel to be transferred to the gel dispenser 229 and via the line 231 is passed on to a similar but opposite gel dispensing device 233, both devices being provided with relatively limited and flattened openings or nozzles, as is clearer from Fig. 5. Preferably, they also include additional supporting devices for the gel when it leaves the nozzles. , which devices contribute to the belt maintaining its shape and controlling its flow direction. The pump 219 can be set to control the feed rate of the gel so that by controlling the feed rate of the particles it is achieved that the desired quantity of particles can be continuously supplied to the flowing gel. Preferably, the pump 219 is of the same type as the previously described pump 115. The gel feeding devices or sprayers 229 and 233 and the line 231 are preferably enclosed in a surrounding vessel or container 235 and are generally so located therein that a gel sandwich product with particles inside it, produced in such a vessel, falls vertically or substantially vertically to its bottom near the center of the vessel, from which it can be removed via an outlet communicating with the conduit 237. This outlet (not numbered) is arranged at the bottom of the vessel, and preferably the gel feeding device 233 terminates near the outlet to reduce the creasing of the sandwich strip containing the particles which can cause entrapment of air (when vacuum is not used). Preferably, the shape of the outlet should correspond to the shape of the band (usually flat and rectangular) and the outlet be adapted to the band to minimize clogging when discharging the toothpaste from the surrounding vessel 10 15 20 25 30 454 945 26 and thereby to a minimum reduce downtime, entrapment of air and solubilization of the binder in the particles.

The particles to be added to the dental gel in a predetermined amount are present in a hopper 230 with adjustable feed device 232, preferably of spiral type, connected to a motor 234 combined with a speed regulator, which feed device discharges the particles at a desired controlled speed via a tubular outlet 236 on a distribution device 238, which disperses the particles so that, when leaving the same, they form a descending stream or curtain which in size and direction corresponds to the bands produced by the nozzles 229 and 233. Instead of a spiral feeder, other types such as screw feeders, belt feeders and vibration feeders are used. The line 228 is connected to a vacuum source which, like the vacuum line 259, can both be and not be activated or connected.

The valves 239 and 241 are arranged to selectively allow the product to flow down the line 243 or be passed to the pump 245, which is preferably of the Moyno type. The screw pump 245, driven by the motor 247, gently pumps the product through line 249 to a static mixer 251, preferably of the Kenics type, where it is gently mixed without disintegrating or solubilizing the particles therein into a homogeneous mixture. The product then passes via line 253 to a container 255, which may be a feed tank for a tube filling machine, not shown. Although the device and method can be used without the use of vacuum, it is often desirable, in order to avoid entrapment of air in the dental materials, that the whole process or a part thereof be carried out under vacuum. Preferably, the particle feeder 10 15 20 25 30 35 454 945 27 and the particle "applicator" under vacuum and consequently the lines or taps 259 and 228 shown in the drawing.

Figure 5 shows the gel feeding devices 229 and 233, which include nozzle portions 275 and 277 with limited flat openings 263 and 265, respectively, the nozzle portions, as shown, being connected to support and guiding devices 267 and 269, respectively, which are adjustable. and which help to properly guide the gel bands or paths so that the curtain or screen of particles correctly falls on them. The gel band on the guide device 267 has the numeral designation 271, and it is shown without any particles being applied thereto. A similar band 272 on the guide device 269 emits its gel band during the discharge from the first guide device and near the outlet from the vessel. Preferably, the curtain of particles falls vertically or substantially vertically on the gel band 271 after it has left the guide device 267, but while it is still moving in a direction with a horizontal component of eg 600 in relation to the horizontal direction. However, if one is careful, some particles may be caused to fall on the gel 271 while it is still in contact with the support substrate. When the gel band 271 with adhesive particles falls down vertically or substantially vertically, it comes into contact with the band 272 and the two bands are stored on each other with the particles in between. To avoid creasing, which can cause entrapment of air, the guide device 269 can be extended either straight or in the form of a convex curve almost all the way to (usually 5 - 25 cm) from the outlet opening from the vessel, and the gel band passes through the aligned and similarly designed outlet without creasing, the discharge rate being the same as the sum of the feed rates. The feed rates (and thicknesses) of the gel strips may be approximately the same or may vary, with the relative rates generally being in the range of 1: 4 and 4: 1. The regulated and proportional feeding of separated particles takes place from the outlet pipe 236 to the distribution device 238, which is shown in the form of an ever wider slide, consisting of side walls 279 and 281, a bottom plate 283 and distributing pins 285 arranged in accordance with "Pascal's triangle". The particle and gel feeders and the nozzle outlet openings of the gel dispensers may be adjustable, as described with reference to Fig. 3. The first or upper gel strip stream is conducted so that the stream or curtain of particles, usually having a thickness of 0.5-5 mm, can fall flawlessly thereon, preferably by the particles falling substantially vertically and the gel moving in a direction with a horizontal component, so that the gel passes under the falling particles, which come into contact with and The gel strip 271 falls down to the right according to the drawing, while the particles 273 fall down on it. the same from the distribution device 238 and the control device 235 (Fig. 4), and the belt 272 falls downwards to the left below the belt 271.

The described devices according to Figures 2 - 5 and the corresponding methods enable dotted toothpastes to be produced efficiently and quickly without the need for using a conventional shear-affecting mixing device. The particles do not clump together, nor do they decompose as this is a rapid process in which the product is quickly prepared and can be filled into tubes before any significant softening or solubilization of the binder in the toothpaste has taken place. The preferably clear toothpaste gel, with usually individually visible, separate functional particles attractively distributed therein, can thus be prepared without it being in any way obscured due to decomposed particles and scattering of the atomized functional material, as a polish, in the toothpaste.

Other advantages of the present invention are the immobilization of the particles in relation to the gel band and the resulting minor dissolution of the binder used in any dissolving material which may be present in the gel. Feeding the gel in an arc that becomes vertical above the outlet of a vessel after the particles have been applied reduces the residence time in the apparatus before removal therefrom, thereby reducing the dissolution of the binder in the particles and preventing the decomposition of the particles. In addition, the sandwich effect, as shown in Figures 4 and 5, means that the particles are more evenly distributed in the dental material, which is a special advantage when it comes to toothpaste compositions in which the particles do not adhere sufficiently strongly.

Broadly speaking, the method of making a toothpaste containing dispersing discrete particles provides a stream of a gel or paste-like dental composition containing a gelling agent which helps the particles to adhere to its surface, which dental composition is disturbed. the part consists of toothpaste, produces a stream of particles intended to be distributed in the toothpaste, directs the particle stream towards a surface of the stream of dental composition and sets the relative feed rates and ratios of the streams of dental composition and particles to be dispersed in the toothpaste, when the particle stream comes into contact with the stream of dental composition the particles, which are insufficient to cover the surface of the dental composition, adhere to the stream of dental composition, whereby a toothpaste is obtained containing particles which in a desired proportion are distributed therein. An apparatus for carrying out the described method comprises a device for producing a moving or flowing stream of a dental composition, which is generally a toothpaste without the particles to be distributed therein, and of such nature that the particles adhere to it. In the apparatus, a stream or band of dental gel is provided by forcing the gel through a suitable orifice so that it is ejected from the orifice with a desired shape, preferably in the form of a flat band, the stream or curtain of particles having a particle size within the range of 10-80 of the U.S. Sight Series, and the particles are directed toward the gel band so that they are evenly distributed on the inner portion of the surface of the liquid band to adhere thereto, and the gel band with the particles adhering thereto is collected in a surrounding vessel, from which it is continuously withdrawn in the form of a gel containing added particles. According to a preferred embodiment of the invention, the particles are inserted between two bands of toothpaste, the particles being formed into an evenly falling curtain by means of a locking device arranged in accordance with Pascal's triangle.

The following examples illustrate but do not limit the invention.

In the entire description, including the exemplary embodiments, and in the claims, all parts are by weight unless otherwise indicated.

Example 1 5 parts of ethylcellulose (10 cP), with the physical properties specified in the above description, in powder form were dissolved in 5 parts of ethanol (95%) and mixed in a Hobart mixer together with 95 parts of calcined alumina (Microgrit WCA 9F) with the particle size in the range 0.5 - 10 microns and an average particle size in the range 3 - 5 microns. The mixing was continued for about 4 minutes until the mixture was homogeneous, after which it was passed through a No. 10 sieve (American sieve series), and the "injection molded" material was dried in an oven for 1 hour. at 65 [deg.] C. The dried agglomerate was sieved through a No. 30 sieve, and the fraction remaining on a No. 60 sieve was collected, which particles consisted of calcined alumina and ethylcellulose.The particles produced had an angular shape, whereby the ratio of maximum length to maximum width was generally in the range of 1 to 2 and most of the particles were such that the ratio was in the range of 1.1 to 1.5 The angular shape of the particles may be a factor in the production of attractive looking toothpastes. at least for some consumers.

A transparent (or translucent) toothpaste base (all components except the particles) was prepared from the following components: Component Parts by weight Glycerol (99.3% purity) 25.00 Sodium carboxymethylcellulose 0.35 Sorbitol (70% aqueous solution) 36.04 Polyethylene glycol 600 3, 00 Water 3.00 Sodium saccharin 0.25 Sodium benzoate 0.50 Blue dye (FD&C Blue no 1, 1% 0.20 aqueous solutionl Sodium monofluorophosphate (1-60 microns) 0.76 Silica (Zeo 49) 18.00 Synthetic silica (Syloid 244 ) 5.50 Sodium lauryl sulphate 1.20 Flavor (green mint, peppermint, winter green, cloves, etc., --- as desired) 95.00 454 945 10 15 20 25 30 35 32 5 parts by weight of the particles described, with the particle size -30 + 60 (American screen series) was carefully mixed in a slow-moving mixer (approx. 2 rpm) with 95 parts of the described toothpaste base, after which the mixture was vented and automatically filled into tubular cap-compressible tubes, which were then sealed During the filling, deaeration and filling steps, the particles, which were mainly evenly distributed in the toothpaste, remained separate, individual and undissolved in the toothpaste base, so that when the tube was opened after filling, especially after storage for about 1 month, and the toothpaste was squeezed out through the opening, the particles seemed to have retained their original integrity and contrasted with the blue-colored gel. When testing the product immediately after filling, without storage, the particles were noticeable, but if stored before use for a period of between 2 weeks and up to 1 year or more, the particles were sufficiently softened by solubilizing the ethylcellulose by the the aromatic oil and sometimes with the help of the dental detergent or any other present surfactant and other components, in order to appear distinct without "smearing" but still to a satisfactory degree of imperceptibility.During toothbrushing with the toothpaste the size of the particles is quickly reduced, and these have no irritating effect on the gums and can be easily removed from the oral cavity after brushing.Although the presence of the anionic detergent in the dental base can be helpful, it is likely that the regulating component in the base is the presence of 1.2% flavoring Presence of such or a mixture of several such agents in a quantity of 0.5 - 2%, preference s - 0.8 - 1.5%, of which at least half is normally active as a solvent for ethylcellulose, is desirable to obtain the best particle suspensions, and the flavoring agent should generally include more than 50% and often more than 80% solubilizing hydrocarbons. , esters, alcohols and aldehydes. The method described for preparing a toothpaste in which the particles are dispersed in the gel-like main mass is a method in which the mixing process is to be monitored to ensure that the particles do not disintegrate, and at any sign that this is the case. the mixing should be stopped and, provided that the appearance of the toothpaste has not markedly deteriorated, usually by making it unacceptably cloudy, the product shall be immediately filled into tubes. Instead of applying the described mixing method, it can often be advantageous to use some other technique in the process, as mentioned above, whereby a controlled even "fan" of particles is applied by gravity to a continuously falling sprayed band of gel. on which the particles adhere, whereby an even distribution of the particles in the toothpaste is obtained.

When the spotted toothpaste is packaged in a compressible aluminum tube, the particles in the toothpaste do not become visible until it is squeezed out of the tube, but they then exist as individual particles in the squeezed toothpaste and give it an attractive and characteristic appearance.

If, instead of ordinary aluminum tubes, elastic transparent tubes are used, such as tubes of polyvinyl chloride or any other suitable polymer, the particles become visible through the tube and the transparent base of toothpaste gel and the movement of the particles when the toothpaste is removed can be observed. This is an additional aesthetic advantage and helps to make toothbrushing more interesting, especially for children. In addition, the functional particles help a person using the toothpaste to remember the presence of polish and other functional ingredients in the toothpaste, which helps to remind him of the importance of the toothbrushing being performed so that the components are effective. 454 945 10 15 20 25 30 34 The above composition relates to a toothpaste gel in which the normal amount of 41.04% sorbitol solution has been reduced to 36.04% to allow the mixing of 5% particles. The purpose of this change in composition is to maintain the percentages of the other components in the toothpaste at the same level as in the non-particulate product, with the exception of the main component, the sorbitol solution. It should also be appreciated that with other variations in the particle content of the toothpaste, such a procedure for modifying the composition may also be applied. It is also possible to start from the original gel composition, for example containing 41.04% sorbitol solution and proportionally reduce the content of each of the components to enable the addition of a desired percentage of particles.

In a variation of the experiment described above, 1% ultramarine blue pigment can be used instead of 1% Microgrit so that the particles get a clear blue color. Instead of the specified quantity of ultramarine blue, 0.5 - 2.0% of this pigment can be added, or mixtures of pigments and polishes in the proportions from 1:10 to 10: 1 can be used. Alternatively, about 0.1 - 1% of any suitable water-insoluble (or oil-soluble) dye may be used. In this case, the color solution can be excluded in the composition relating to the toothpaste base, or may be present provided that sufficient contrast between the particles and the toothpaste base can be obtained.

Of course, the various components of this composition can be exchanged for others, such as those previously described, while obtaining useful products. For example, the various pigments and dyes mentioned may be used, the sodium lauryl sulphate may be exchanged for higher sodium ethoxylated fatty alcohol sulphate or sodium monoglyceride mono-sulphate of hydrogenated coconut oil fatty acids, and the polishing agent / dihydrogen may be exchanged calcium phosphate (anhydrous) or mixtures thereof. The levels of the various components can be modified in 10%, 120% and 130%, provided that they are maintained within the previously stated limits, and thus satisfactory products with similar properties are obtained, even if the products with the levels specified in this example are preferred.

Example 2 75 parts of anhydrous dicalcium phosphate and 15 parts of dicalcium phosphate dihydrate, both with a fixed average particle size of about 4 microns, were mixed with 10 parts of ethylcellulose and 10 parts of ethyl alcohol in a Hobart mixer.

Alternatively, and preferably, the ethanol and ethylcellulose may first be mixed together and then mixed together with a pre-prepared mixture of the dicalcium phosphate. The formed mass was passed through a sieve with 2000 micron smooth orifices, and then dried in an oven for 1 hour at 65 ° C. The dried agglomerate was then sieved through a 420 micron smooth orifice sieve, and the agglomerate that did not pass through a 177 micron orifice sieve was collected. Thereafter, the resulting agglomerated functional particles were mixed with a toothpaste base having the composition given in Example 1, except that the polish in this base was exchanged for sodium aluminosilicate, such as that sold under the trademark Zeolite 4A, and the percentage of particles in the final the product was 2% (increasing the content of the sorbitol solution present by 3%).

In variants of this composition, instead of the polishing agent in the particles, hydrated alumina having an average particle size of less than about 7.4 microns in diameter, or insoluble sodium metaphosphate having an average particle size of about 5 microns (whereby all sizes are maximum particle sizes). ' The toothpastes according to this example are spotty, transparent or translucent products with an aesthetically pleasing appearance. The visible particles of agglomerated polish (which can be completely or partially exchanged for other functionally insoluble materials) are mainly evenly dispersed in the toothpaste base in the form of visible separate units and they are not completely imperceptible when used after three months of storage.

Example 3 Instead of dissolving the ethylcellulose in ethanol or any other suitable solvent, agglomerates were prepared by mixing the polish and the ethylcellulose, in some cases with a reduced quantity of ethanol present, to obtain a powder mixture. The mixture was pressed in a rotary tablet press into tablets with a thickness of about 6 mm and a diameter of about 25 mm. The tablets were granulated in a vibrating granulator to obtain smaller particles, preferably those which passed through a No. 30 sieve and remained on a No. 60 or No. 80 sieve. This method of preparing the particles can also be applied to all the particle compositions given in the preceding examples. Although the binding effect of ethylcellulose may not be as great, according to this example, the products can be satisfactorily incorporated into toothpastes to contribute to their aesthetic benefits and functional effects. If the cohesive effect of ethylcellulose in the above compositions is not sufficient, the present content thereof can be increased, sometimes up to 100 or 200%, but this increase entails additional costs and the "wet" method in which solutions of ethylcellulose in ethanol or any other suitable solvent is used, is therefore often preferred.

Example 4 95 parts of calcined alumina (Microgrit WCA 9F), having a particle size in the range of 0.5 - 10 microns and an average particle size in the range of 3 - 5 microns, were mixed with 3 parts of powdered polyvinylpyrrolidone, obtained from GAF Corp. and sold under the name Plasdone K-29-32. 2 parts of powdered ethylcellulose of the type described in Example 1 were dissolved in 5 parts of ethanol (95%), and the PVP-alumina mixture was mixed with the solution in a Hobart mixer. The mixing was allowed to proceed for about 4 minutes until the product was homogeneous, after which it was passed through a No. 10 sieve, and the "injection molded" material was dried in an oven as described in Example 1. The dried agglomerate was sieved and collected on the same method as in Example 1. The particles produced were angular in shape and the ratio of maximum length to maximum width was generally the same as in Example 1. A transparent (or semi-transparent) toothpaste base (all components except the particles) was prepared in the same manner as in Example 1 except that 39.04 parts of sorbitol were present instead of 36.04 parts thereof. 2 parts of the described particles, with the particle size -30 +60 (American sieve series), were carefully mixed in a slowly rotating mixer (approx. 2 rpm) with 98 parts of the described toothpaste base, after which the mixture was deaerated and automatically filled with compressible tubes, which were then sealed. The product preparation applied was the same as described in Example 1. When testing the product immediately after filling, without storage, the particles were noticeable, but after it was stored before use for a period of between 2 weeks 454 945 10 15 20 25 30 38 and up to 1 year or more, the particles were sufficiently softened to be imperceptible, by PVP solubilizing the present water and ethylcellulose solubilizing by the aromatic oil, both solubilizations apparently in some cases also using the dental detergent or any other surfactant that may be present, and in some cases assisted by other components.

When the content of flavor in the dental gel base is reduced to 0.6%, half the amount in the above composition, the system of PVP-ethylcellulose binders in the particles is still effective and these become satisfactorily imperceptible during storage. It also remains effective when the concentration of flavor changes to 0.3%, 0.9% and 1.5%. However, the higher levels of flavor (and / or other lipophilic solvents) may cause a slightly earlier solubilization than desired, in which case the levels of PVP and ethylcellulose should preferably be changed to, for example, 2 parts of PVP and 3 parts of ethylcellulose. If the perceptibility of the particles should increase, so that it becomes larger than desired, they can also be made softer by increasing the content of PVP, for example to twice the content of ethylcellulose. The concentration of particles and their size can also change, within the previously given ranges. Other of the materials listed above may also be used in place of the alumina polish, including other types of water-insoluble functional substances.

The variations with respect to the composition and method of preparation described in Example 1 can also be applied in this example, the products obtained also being useful particles and dotted toothpastes. 10 15 20 25 30 454 945 39 Example 5 75 parts of anhydrous dicalcium phosphate and 15 parts of dicalcium phosphate dihydrate, both with a maximum average particle size of about 4 microns, were mixed with 5 parts of ethylcellulose, 5 parts of PVP and 10 parts of ethyl alcohol in a Hobart- mixer. Alternatively and preferably, ethanol and ethylcellulose are first mixed together, after which these are mixed with a pre-prepared mixture of dicalcium phosphates and PVP. The resulting mass was passed through a sieve with smooth openings of 2000 microns, after which the product was dried in an oven for 1 hour at 60 ° C.

The dried agglomerate was sieved through a 420 micron smooth orifice sieve, and the agglomerate that did not pass through a 177 micron orifice sieve was collected. The resulting agglomerated functional particles were then mixed with a toothpaste base having the composition given in Example 4, except that the polish in the base was exchanged for sodium aluminum silicate, such as that sold under the trademark Zeolite 4A.

The toothpastes according to this example are spotty, translucent or translucent products with an aesthetically pleasing appearance. When the same variations in composition and preparation as in Example 2 are applied, good products with the desired properties are also obtained.

Example 6 The functional polishing component of Example 5 was replaced with a mixture of 10 parts of anhydrous dicalcium phosphate and 90 parts of calcium carbonate, using the same total content of polishing agent; otherwise the same procedure was applied. The resulting products were also satisfactory in terms of functional effects and their appearance was aesthetically pleasing. Similar results were obtained when different mixtures of the polishes were used instead of this mixture in the particles, and when the proportions thereof were varied.

Example 7 Instead of dissolving the ethylcellulose and PVP in ethanol or any other suitable solvent, agglomerates, similar to those of Example 6, were prepared by mixing polishing agents, PVP and ethylcellulose, sometimes in the presence of a reduced ethanol content, to obtain a powder mixture. .

The mixture was pressed in a rotary tablet press, whereby tablets with a thickness of about 6 mm and 25 mm in diameter were obtained. The tablets were granulated in a vibrating granulator to obtain smaller particles, preferably those which passed through a No. 40 sieve and remained on a No. 60 or No. 80 sieve. Although the binding effect of PVP and ethylcellulose may not have been as great, the products according to this example were nevertheless satisfactory for incorporation into toothpastes and contribute to their aesthetic benefits and functional effects. If the binding effect of PVP and ethylcellulose in the foregoing compositions is not sufficient, the present levels thereof can be increased, sometimes by up to 100% or 200%, but this increase means increased costs why the "wet" method in which solutions of PVP and ethylcellulose in ethanol or any other suitable solvent are often used.

Example 8 Polyvinylpyrrolidone, which in the previous examples was the water-soluble part of the combined binder, was partially (SO%) or completely replaced by the following water-soluble binders: gum arabic, gelatin, maize starch, sodium carboxymethylcellulose, sodium alginate, polyvinyl alcohol, carvinyl alcohol, xanthan gum and gum tragacanth. When the particles produced were incorporated into toothpaste gels, such as those of the above examples, they sufficiently retained their individuality and integrity during product processing, and became imperceptible upon storage in the toothpaste while retained its original shape, as did the particles containing the binder combination of PVP-ethylcellulose. However, the combined PVP-ethylcellulose binder is generally judged to be superior in the combination of desired properties, such as stability in product preparation, compatibility with toothpaste components and the conversion from noticeable to non-noticeable without loss of particle integrity and without marked change of appearance.

Example 9 Particles of different compositions were compared with particles based on ethylcellulose and PVP. The particles of the invention were generally prepared in the manner described in Example 4 by the wet method, and the particle composition included 95% calcined alumina, 2% ethylcellulose and 3% PVP, these materials being the same as in Example 4. The particles prepared in the comparative experiment were also prepared by the wet method, with the exception of one type, which will be defined, which was prepared by the dry "tablet method" of Example 7.

The particles were tested by weighing 100 mg of each type, placing them separately on slides, adding 4 drops of water each, covering each slide with a different slide, and noting the time of physical change and the type of physical change of the granulate. . When 2% sodium carboxymethylcellulose was used as a binder, the particles lost their integrity within 15 seconds, as was the case with the particles bound with 2% hydroxypropylmethylcellulose, but this took 2 minutes. Particles prepared with a binder containing 2% methylcellulose and 3% PVP softened, swelled and lost their integrity after about 2 minutes, and when S% PVP was used as the sole binder the particles thus produced softened after 8 minutes. When the binder was 1% methylcellulose (400 cP), the particles lost integrity after a little more than 5 minutes, and when the binder was changed to 10% polyethylene glycol 6000, together with 1% magnesium stearate, and the particles were prepared by "tablet pressing", the integrity lost. after 19 minutes. When the "control" particles of the invention, containing 2% ethylcellulose and 3% PVP, were subjected to the same experiment, they were still intact after more than 6 hours.

Example 10 In a process according to the invention, using the device according to Figures 2 and 3, a particulate clear toothpaste gel was prepared with the composition and in the manner described in Example 1. The various gel (or paste) components were mixed together in the mixer 111 and was pumped, preferably with a Moyno-type pump to the sprayer which ended in a flat "slotted" nozzle, as shown, with a relatively narrow rectangular opening. Preferably the nozzle should slope downwards relative to the horizontal line with a angle of about 10 - 450, eg 300.

The feed rate of the particle feeder, an Acrisan screw feeder, was set relative to the feed rate of the gel. For example, when a particle content of 3% in the toothpaste was desired and the feed rate of the gel was 3 kg / min, the feed rate of the particles was 93 g / min. Conventional electronic or mechanical devices can be used to maintain the desired ratio of feed rates, or to set the same if a different ratio is desired in other products. 10 15 20 25 30 35 454 945 43 - Fig. 2 shows only schematically the particle feeding device, and only the end of it is shown in Fig. 3, and different types of feeders, including screw feeders, belt feeders, belt scales, electronically controlled gravimetric feeder etc., can be used and the pattern at the supply can be changed. The application should be made in such a way that only a few, if any, particles fall outside the gel, and the gel stream should retain the falling particles. The particles should fall apart and the gel should move fast enough under them, at a speed of generally 10 - 100 cm / sec, eg 20 - S0 cm / sec, so that the individual particles hit the gel and stick to the same, with very few particles hitting other particles and repelling them. All or virtually all such repelled particles will later adhere to the dental gel.

The precipitated particulate gel, with the particles adhered thereto, does not remain for any longer period of time in the enclosing vessel in which or above which the particulate feeder is located, as it falls into the vessel section and most of it is almost immediately passed. on to the outlet. This short residence time in the "particle additive vessel" is highly desirable as it helps to maintain the integrity of the particles in the toothpaste. Although the residence time in the vessel may vary, the time is generally in the range of 20 seconds to 2 minutes, the shorter the better. The rapid passage, the absence of moving particles and the central gel outlet from the vessel also help to avoid coagulation of the particles into undesirable lumps. The extra volume of the surrounding vessel is for retaining gel that can be fed into it during periods when the filling device is temporarily stopped, before the feeding to the vessel can be interrupted.

Thus, the vessel may often contain only a relatively small amount of particulate gel, for example 10-25% of the volume of the vessel. Alternatively, other materials may act as a "wall" defining the particulate gel within the vessel.

After leaving the particle addition vessel, the gel is carefully pumped on with a Moyno-type pump and passed through a static mixer to ensure complete mixing. The preferred static mixer, a Kenics mixer, is similar to that described in 1973, by Chemical Engineering, in an article entitled "Handling Viscous Materials - in the March 19 issue of Motionless Mixer for Viscous Polymers". Although it is desirable that a mixer be used before the gel is transferred to a filling machine or a suitable container before such a machine, it is often possible by means of the method and apparatus in question to sufficiently distribute the particles throughout the gel, so that in some cases do not need to be used.

The working conditions are not considered critical, but in general the vacuum used should be in the range of about 300 - 700 mm Hg, eg 400 - 600 mm Hg. The temperatures can be about room temperature or higher, for example in the range 10 - 40 ° C.

The pressure at the injection of the gel varies with the viscosity of the gel, but between 0.03 and 0.7 kg / cm 2 can be considered a reasonable range.

Since they are used in the manufacture of an oral product, the various parts of the equipment according to the invention must be made of corrosion-resistant and safe materials.

It has been found that stainless steel components are highly desirable, and mixers, sprayers, pumps and valves as well as other parts which come into contact with liquid or gel material should preferably be made of stainless steel, such as that normally used. turned in the food industry. When a 2% particulate clear toothpaste (containing silica, sorbitol, glycerol, CMC, sodium lauryl sulfate, flavoring and water in the gel, and alumina and ethylcellulose in the particles), such as that described in Example 1, prepared by means of the apparatus described here, a product is obtained exactly as desired, in which the particles are evenly distributed throughout the clear gel and without signs of any turbidity or decomposed particles. Similar results are obtained when other particulate toothpastes, such as those of the prior art and of Examples 2 to 9, are prepared using the apparatus and method as described. Although the dental gel or paste in the application of the method should preferably be in the form of a flat strip, variants of this shape can of course be used, such as arcuate strips and also cylindrical or tubular streams. Likewise, although it is preferable that the stream or curtain of particles is a straight curtain of such material of suitable thickness, eg 0.1 mm to 1 cm, preferably 0.5 - 5 mm, which curtain falls down due to weight - the force, then the particles can be forcibly transferred to the toothpaste.

For example, in some cases it is possible to apply particles to a stream of toothpaste that moves vertically, horizontally, whereby those that do not get stuck are collected to return. The flow of dental material can be given a rotating motion, so that around the entire exposed surface it "picks up" particles which from the same direction are directed towards it. Guided particles can be made to abut the gel stream and settle thereon, immobile and separated. Although such variants of the invention are useful, the method described and illustrated herein is considered superior.

The quantity of particles fed to the moving belt or web of toothpaste gel should constitute a smaller proportion compared to the complete toothpaste containing particles and compared to the fed gel. The feed rate of the particles should generally be adjusted so that the amount of particles directed at the gel is insufficient to cover it, and preferably it should be insufficient to cover half the surface of the part of the gel exposed to the curtain of particles, when such a curtain comes in contact with the gel. Although various ways of causing the particles to adhere to the gel band have been described, as mentioned earlier, it is highly desirable that the particles fall vertically in the form of a curtain down on the gel band with the gel moving in a direction with a horizontal component. . The direction may be horizontal or have a clear horizontal component, the gel falling downwards after picking up the particles, but usually a slope in relation to the horizontal line of eg 10 - 600 is preferred for the gel, while the particles fall vertically after leaving the supply device. The viscosity of the gel is not critical as long as the particles adhere satisfactorily to it, and the particle size is not critical either, but in general it is within the sieve range no. 10 - 80, preferably 30 - 80 and in particular 30 - 60. The particles have preferably sharp edges and when they fall on the gel stream they are partially embedded in it and become immediately immobile, but the same good results can also be obtained when round particles are used. Although the particles are preferably visible in a clear gel, making the product aesthetically pleasing, they may have a refractive index that makes them invisible. The term "particles" thus includes visible and invisible discrete particles of different materials, with agglomerates of finely divided polishing agent being preferred. Thus, although it is preferred that the particles consist of an agglomerate of finely divided polish and binder, they may still contain other "active" components, such as therapeutic agents, dyes, flavors and fluorides. 10 15 20 25 30 35 * f 454 945 Ã- fl 47 All the toothpaste materials on which the particles have been applied have been toothpastes, without particles, but this is not necessary. It is possible to mix some dental components into the other toothpaste materials after the addition of the particles. For example, it may be desirable for the flavoring agent, which may contain some volatile components, to be mixed in before the Kenics mixer but after any vacuum treatment of the product during the addition of the particles. This process has the advantage that the flavor is preserved and protected from loss of the more volatile components therein due to the application of vacuum to the particle mixture, and any components of the flavor that would solubilize the binder in the particles would otherwise occur during a shorter treatment time. in contact with the same. However, the Kenics mixer or other static mixer with low shear stress mixes the flavor sufficiently evenly throughout the toothpaste. Likewise, other components, usually minor additives, may be added to the toothpaste after the particles have been mixed therein.

The said enclosing vessel, in which the toothpaste with applied particles falls down, can be under vacuum or be open to air. The particle feeding device may have a container arranged below it, instead of being enclosed in a vessel. However, such equipment should preferably be covered and under vacuum, as entrapment of air would otherwise be a problem. It acts as a container for the particle feeding device, except that it is a vessel for collecting the resulting product. The method and apparatus of the invention can be used to make a variety of toothpaste compositions containing different levels of particles. Changing the concentration of particles is a simple matter, since you only need to change the speed of the particle feeder and adjust the feed of the gel accordingly. Of the various advantages of the invention may be mentioned increased efficiency in the process, reduced use of mixers with moving parts and the stabilization of the dental gel or paste. It is known that certain toothpastes are thinned by excessive mechanical processing, and the manner in which particles are mixed into the toothpaste means that such processing is avoided and that the desired viscosity of the dental gel can be maintained.

Example 11 A particle-containing toothpaste was prepared in the same manner as in Example 10, but using the apparatus illustrated in Figures 4 and 5. Two gel bands were produced, each consisting of half the total amount of toothpaste (smaller amount of particles). . The flat slotted nozzles had a downward slope of about 300 relative to the horizontal line. The gel speed was about 20 - 50 cm / sec, and preferably the gel should be so adherent and the conditions so adapted that most particles encountering the first gel stream adhere to it, while the other (or almost all other) particles are introduced between the gel bands of the second gel stream.

The particle feeding device according to Fig. 5 is a slide on which pins are arranged in accordance with Pascal's triangle. It is inclined downwards at an angle of about 30 ° in relation to the horizontal line and it has at the portioning end a width which is about 90% of the width of the gel stream. Although the pin arrangement in accordance with Pascal's triangle is preferred, other feeding devices can of course be used.

The toothpaste produced had the same advantages as that of Example 10. The method and apparatus of this example are particularly suitable for retaining the particles in the toothpaste in a specific manner and evenly distributed therein, when the gel is not highly adherent.

"Rejection" of the particles is thus avoided, thus avoiding loss of particles and also not having to return or discard such particles that have not stuck. In addition, even with non-stick gels (and / or non-adherent particles) a definite end product can be prepared with even and desired content of particles therein (since the loss of particles is reduced to a minimum).

The present invention has been described with reference to various examples and preferred embodiments, but is not limited thereto, as one skilled in the art upon the present disclosure clearly recognizes that it is possible to use other replacement materials and equivalent components, without, therefore, goes beyond the scope of the invention.

Claims (9)

10 15 20 25 30 454 945 50 P a t e n t k r a v Functional agglomerated particles intended to be incorporated into toothpaste, characterized in that they consist of an agglomerate of a water-insoluble powdery functional material and a water-insoluble, ethanol-insoluble ethylcellulose, that the water-insoluble powdery functional material is a dental polish which constitutes the largest part of the particles, the ethylcellulose being the smaller part of the particles, that the water-insoluble dental polish is selected from the group consisting of dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, silica, magnesium carbonate, calcium carbonate, calcium carbonate mixtures thereof, with a particle size in the range 0.5 - 20 microns, the size of the particles being such that they pass through a No. 10 sieve according to the American sieve series and are retained by a No. 80 sieve, and the polishing agent constitutes 75 ~ 98% of the particles, ethylcellulose makes up 2 - 20 % thereof and the dye, when present, constitutes up to 5% thereof. Particles according to claim 1, characterized in that they contain 85 - 97% dental polish, 3 ~ 15% ethylcellulose and 0.1 - 1% dye, the particles having such a size that they pass through a No. 30 sieve according to the American sight series and is maintained by a No. 80 sight. Particles according to claim 1, characterized in that they contain a water-soluble binder. Particles according to claim 3, characterized in that the water-soluble binder is polyvinylpyrrolidone (PVP), wherein the combination of binder, consisting of water-insoluble ethanol-soluble ethylcellulose and PVP, constitutes a smaller part of the particles. Particles according to claim 4, characterized in that the ratio of ethylcellulose to PVP is in the range 1:10 to 10: 1, with respect to weight. Particles according to claim 5, characterized in that the ratio of ethylcellulose to PVP in the particles is in the range 1: 5 to 5: 1. Particles according to claim 6, characterized in that the dental polish comprises 80-98% of the particles, the ratio in the binder between ethylcellulose and PVP being in the range 1: 2 to 2: 1. Particles according to claim 7, characterized in that they contain 85 - 97% dental polish and 3 - 15% of the combination of binders, and their particle size is such that they pass through a No. 30 sieve according to the American sieve series but are retained of a No. 80 sieve, the ratio of ethylcellulose to PVP in the particles being in the range 1: 2 to 1: 1. Particles according to claim 8, characterized in that they contain 90 - 97% calcined alumina such as the dental polish and 3 - 10% of the combination of binders, wherein the ratio of ethylcellulose to PVP is about 2: 3.